import React, { Component } from "react";
// 引入 store，用于获取 redux 中状态
import store from "../../redux/store";
// 引入 actionCreator，专门用于创建 action 对象
import {
    createIncrementAction,
    createDecrementAction,
} from "../../redux/count_action";

export default class Count extends Component {
    state = { carName: "奔驰c63" };

    // componentDidMount() {
    //     // 检测 redux 中状态的变化，只要变化，就调用 render
    //     store.subscribe(() => {
    //         this.setState({});
    //     });
    // }

    /**
     * 加法
     */
    increment = () => {
        const { value } = this.selectedNumber;
        store.dispatch(createIncrementAction(value * 1));
    };

    /**
     * 减法
     */
    decrement = () => {
        const { value } = this.selectedNumber;
        store.dispatch(createDecrementAction(value * 1));
    };

    /**
     * 奇数加
     */
    incrementIfOdd = () => {
        const { value } = this.selectedNumber;
        if (store.getState() % 2 !== 0) {
            store.dispatch(createIncrementAction(value * 1));
        }
    };

    /**
     * 异步加
     */
    incrementAsync = () => {
        const { value } = this.selectedNumber;
        setTimeout(() => {
            store.dispatch(createIncrementAction(value * 1));
        }, 500);
    };

    render() {
        return (
            <div>
                <h1>当前求和为：{store.getState()}</h1>
                <select ref={(c) => (this.selectedNumber = c)}>
                    <option value="1">1</option>
                    <option value="2">2</option>
                    <option value="3">3</option>
                </select>
                &nbsp;
                <button onClick={this.increment}>+</button>&nbsp;
                <button onClick={this.decrement}>-</button>&nbsp;
                <button onClick={this.incrementIfOdd}>
                    当前求和为奇数再加
                </button>
                &nbsp;
                <button onClick={this.incrementAsync}>异步加</button>&nbsp;
            </div>
        );
    }
}
